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Seems Mr. Curl isn't interested in participating in an experiment designed to duplicate his measurements. Pray tell us why....
Follow Ups:
Damn, I am so glad that is over with. Well maybe. I am sure there shall still be room for argument over test methodology and results to come.I think alot of you would make great lawyers. Tenacious, insulting and persistence are all fine traits in lawyers. That is a compliment BTW!
Will be intresting to see the results.
NS
Kuribo, I once thought that you might be an adult, but now I see you as a teenager. The truth is that I want to control my own measurements. If someone, somewhere gets a null result with their test equipment, I will take note, but I still get different distortion results with the cables in my lab. However, some things have changed. For example, most of my RS cables now measure pretty good, but some other cables measure pretty bad. I think this is do to 'break-in' , another 'imaginary' mechanism that I find useful in understanding audio performance. I also think that contact oxidation (internal to the connector, as I clean the external parts of the connector) might also be an added factor because my worst cables are more than 10 years old. The oldest, and worst measuring cable, at the moment is about 20 years old, but is well made, with Tiffany connectors on each end. This was a surprise.
I didn't get any response from you, Kuribo, as to what you know about measuring equipment? Have you ever measured any audio components. I think we should put things into perspective.
And I concur with Kuribo.. What he knows about measuring equipment is unimportant here...You are the one claiming the distortion..Why not try to find out if the distortion duplicates between two different setups using the same cable?? The option is there for you.
The most intelligent and sophisticated users of the best equipment in the world cal their equipment..and baseline it..and verify accuracy..traceable to known, worldwide standards...why can't you???
Hmmmm...a teenager...someone who, regardless of the growing mountain of evidence to the contrary, continue to deny that they are incorrect. Seems you fit that description far better than anyone else.
Why not discuss the possible error mechanisms, John??? Rather than deny the possibility that you have been chasing a ghost...
May be there, may not...but you're obviously avoiding being proven wrong..
We all see your actions here...there's no need for that..
Cheers, John
I'm not the one running around making claims like "your cables are full of micro diodes" and "cables exhibit measureable distortion", which have not been verified by anyone, either experimentally or theoretically. You are on your own here, and it is up to you to either back it up incontrovertibly, or back off.You continue to insult ("teenager?" I wish!), obfuscate (just what the hell does my testing experience have to do with YOUR results, huh?), and avoid the issue by babbling on about old cables and god knows what. You want to control your own measurements? I don't recall anyone offering to run your equipment for you...
I know the scientific method as practiced by competent scientists and engineers when I see it, and more to the point in this case, when I don't. You not only show a gross inability to comprehend this basis of scientific inquiry, but you call into question your own credibilty by running away from an opportunity presented to you to put your money where your mouth is. Smacks of cowardice, and gives the impression that you are too small to risk the possibility of error.
You have blustered, insulted, attacked people's education, and generally been a bore and a bully when others have questioned the basis of your measurements. Now, when actually confronted by the results of someone you can't dismiss because he hasn't a college diploma, and has used equipment a generation ahead of yours, you are going to run and hide? Reminds me the scene where Toto finds the real wizard....
Too bad you have invested so much of your ego in this that you can't face up to the possibility that you might be proved wrong, because no matter what the truth of the matter is, it would have helped advance the state of knowledge, and that is something that all music lovers would have benefited by.
Ok folks, this is, once again, the situation.
Yes, it is true that I have mentioned 'microdiodes' as a hypothesis of what I have and still can measure in connecting wires. I have been told by others that this is 'impossible' and that I must have something wrong with my equipment, or worse.
Every suggestion, both plausible and implausible has been put forth. Any suggestion is apparently more plausible than the 'appearance' that maybe, just maybe, the cable itself is the distortion generator. I have tested the plausable suggestions, such as contact interface problems and specific capacitive loading. I have gone through my equipment to the best of my knowledge and I have the manuals for the equipment so I know what and where to adjust, if necessary. I can't find anything wrong with my test set-up.
Now, what about Bruno's test? I don't know who Bruno is, his capacity at Phillips, or whether he daily uses or just borrowed the AP Cascade test set-up that he used to make some similar wire tests. The most important thing is that all his tests were too 'clean'. It might be that he is working in a 'screen room' but usually, external airborne interference will be apparent in any normal environmental setting when measuring at these levels. I don't see anything much.
I was, at some point, challenged by Steve Eddy, to send something to Bruno. I just ignored his suggestion. I don't know Bruno, and all he seems to get are null printouts. This is not the best test atmosphere to find out for sure.
Even so, I could be wrong. If I am wrong, then it is still a mystery to me as to why I get positive results. I will continue to look for the potential problem, if I does exist, and I recommend that those of you who worry about such things should ignore my previous measurements, as they are not proven by separate measurements at the moment.
Now let me give some of you an idea of the measurement itself.
THD testing is simple in concept:
You generate a nearly perfect single tone.
You send the tone through the device under test.
You input the tone, after it has gone through the device under test (DUT) amplify it to a set level, then you use an active filter that acts as a notch. In my case a -95dB notch, in Bruno's case maybe 130dB or better. Bruno has a pretty good notch.
Now what is the measurement bandwidth of the THD analyzer? Well, my setup uses 80KHz, this is much more than the human ear can hear, but that is set by the test equipment. Bruno's bandwidth can be reduced somewhat, because he is using a 1KHz test tone, and I am now using a 5KHz test tone. He does not need as much bandwidth. In his case, this can be an advantage, but in my case it doesn't matter, because I can't change my bandwidth below 80KHz.
Why is this important? Well, without a CASCADE setup, the potential distortion is buried in the noise when measuring below 100 mV or so. Both Bruno and I use a cascade setup, just different equipment.
This is the digital part of the AP Cascade for Bruno and it is the HP3563 FFT analyzer that I use today, or the 'MAC the Scope' FFT program that I used with my MAC years ago.
I upgraded the the HP in order to get faster and better processing of the residual out on my THD analyzer.
Now how do we get improved perfomance by using a cascade set-up? Well, two ways. First, we divide the 80KHz or so spectrum into smaller segments. At this time, I have it broken into 100Hz segments, THEN we can signal average. This is taking a number (100 in my case) of FFT measurements of the SAME test signal and averaging them out. I should get, in theory, about a 20dB improvement in noise reduction. This brings out subtle bumps in the spectrum, usually lost in noise. This is what I measure. I get all kinds of extra stuff as well, rather than just harmonic distortion, I get hum, 15.7KHz TVI, and ultra sonic crap from digital power supplies, unfortunately some of which comes from my HP3563. However, these input can be ignored, because they do NOT lie where the distortion would be if it is generated. After all, harmonic distortion is always a MULTIPLE of the initial tone, so now I get distortion at 10,15,20,25,...KHz respectively, and they lie on a grid in my HP.
This is what I measure, is it real? I can't swear to it, but it works for me.
Yes, it is true that I have mentioned 'microdiodes' as a hypothesis of what I have and still can measure in connecting wires.You have more than mentioned "microdiodes" as a hypothesis, John. On diyAudio.com you recently made the following statement:
Hate to be the one to tell you, BUT there are diodes in your metal wires. More than you will ever bother to measure. I have measured them.
That's no hypothesis, John. That's a declarative statement of fact.
The most important thing is that all his tests were too 'clean'.
Why? Becuase his measurements don't show the huge 15.75kHz spike that yours do?
It might be that he is working in a 'screen room' but usually, external airborne interference will be apparent in any normal environmental setting when measuring at these levels.
It might be that he's not working in an apartment complex full of couch potatoes laying around all day watching TV. That's what you said accounted for that spike in your measurements, yes? That it was due to peoples' TVs in your apartment complex, and that the magnitude of that spike depends on how many people have their TVs turned on.
Other than that 15.75kHz spike in your measurements, I don't see any other signs of intereference in your plots.
I was, at some point, challenged by Steve Eddy, to send something to Bruno. I just ignored his suggestion.
What the fuck are you talking about, John? I didn't challenge you to send anything to Bruno. What I did was offer to SEND YOU SOMETHING.
Once again, and perhaps this time it'll finally seep into what's left of your frontal lobes:
Risch dismissed Bruno's measurements because Bruno wasn't measuring the same cables as you had.
I've an old set of Radio Shack Gold interconnects. I also went and purchased a brand new set of Radio Shack Gold interconnects. As well, I have a set of bog standard A/V interconnects that came with my DishNetwork boxes.
I took each set and separated the left and right channels, resulting in two separate sets of cables, each set comprising an old Radio Shack Gold interconnect, a brand new unused Radio Shack Gold interconnect, and a brand new unused bog standard A/V interconnect.
I will be sending one of these sets to Bruno for him to measure on his System Two Cascade.
I offered to SEND YOU the other set to measure on your system.
This way you could each measure what amounts to virtually the same cables and the results can be compared.
That's the offer that I've made to you several times both here and over at diyAudio.com for over a week now. And that's the offer that you have persistently ignored.
So where do you get this nonsense that I challenged you to send something to Bruno? Are you always in such a drunken stupor that you can't even understand what's written in plain English in the posts that you read even though what's said is repeated to you several times? Or is this just another of your bullshit tactics to twist and mischaracterize?
se
Send me a cable, I will give you the results.
nt
NT
As you have observed, a wider bandwidth will by definition have more noise and be more susceptible to interference. However; keeping the bandwidth, let's say at 30 kHz will reduce this effect. Given that you are finding "crossover distortion" at 5 kHz in your test set and Bruno is not at 1 kHz says more about test equipment and test environment.
As we also have observed the noise floor in Bruno's test set appears to be about 20 db lower than yours if I remember correctly.
In conclusion I will ask you once again to check your test set up and especially the Oscillator in your source equipment. Given your previous statements on earth grounding I will ask the question; Is your HP Analyzer and your Source equipment properly grounded?
Just to clarify things: I use 5 KHz, because my test equipment null is more stable at 5KHz than 1KHz this year. The tests that you are relating to were done YEARS AGO. I now use 5 KHz, as I did when first measuring with my linear spectrum analyzer starting about 10 years ago. I only changed, temporarily, to fit in the 20KHz window of the MAC FFT program. I prefer 5KHz when measuring other things, such as power amps, because it puts more stress on the unit under test.
You have not addressed the other part of my question on grounding. My other question is why is 5 kHz more stressful on wire as opposed to 1 kHz?
It is more stressful on amps and preamps which is what I make for a living. That is why I first improved my equipment in order to make tests like these. Wire is an afterthought.
You still haven't answered my question on grounding.
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